A communication network includes network elements that route packets through the network, predominantly in line card hardware. From time to time, such network elements may communicate “heartbeat” messages to each other in order to verify presence and connectivity among the network elements. Failure of a network element to receive a heartbeat message from another network element within a particular time interval may indicate a failure or fault in the network (e.g., a hardware failure, a forwarded table corruption, or other failure that may cause a network service to fail).
Such network elements may also employ link aggregation. Link aggregation (e.g., IEEE 802.1AX-2008) may generally describe the practice of using multiple network cables or ports in parallel to increase the link speed beyond the limits of any one single cable or port, and to increase redundancy for higher availability. In link aggregation, a group or set of ports may be combined and represented as a single logical port to other components of the network system. Various switching elements of the network system may “see” the aggregated ports (known as a “link aggregation group” or “LAG”) as a single logical communication port in the routing tables or databases of network elements external to the LAG.
Despite the functional advantages of LAGs, traditional LAGs may present challenges to processing of heartbeat messages. For example, a heartbeat message from an upstream network element may not be received because the upstream network element may forward the heartbeat message to a LAG port on a line card different from where the line card that is processing heartbeat messages. Existing solutions to this challenge often employ a centralized software approach. Such a centralized software approach may add complexity and reduce performance in situations where heartbeat message processing would otherwise be handled predominantly in hardware.